This is a note to let you know that I've just added the patch titled
staging: android/lowmemorykiller: Don't unregister notifier from atomic
context
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
staging-android-lowmemorykiller-don-t-unregister-notifier-from-atomic-context.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 1eda5166c7640092f512138be6899d050c3d62ed Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <[email protected]>
Date: Wed, 7 Mar 2012 17:54:00 +0400
Subject: staging: android/lowmemorykiller: Don't unregister notifier from
atomic context
From: "Paul E. McKenney" <[email protected]>
commit 1eda5166c7640092f512138be6899d050c3d62ed upstream.
The lowmemorykiller registers an atomic notifier for notfication of when
the task is freed. From this atomic notifier callback, it removes the
atomic notifier via task_free_unregister(). This is incorrect because
atomic_notifier_chain_unregister() calls syncronize_rcu(), which can
sleep, which shouldn't be done from an atomic notifier.
Fix this by registering the notifier during init, and only unregister it
if the lowmemorykiller is unloaded.
Rebased to -next by Paul E. McKenney.
Rebased to -next again by Anton Vorontsov.
Signed-off-by: Rabin Vincent <[email protected]>
Signed-off-by: Christian Bejram <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Reported-by: John Stultz <[email protected]>
Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/staging/android/lowmemorykiller.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
--- a/drivers/staging/android/lowmemorykiller.c
+++ b/drivers/staging/android/lowmemorykiller.c
@@ -73,10 +73,10 @@ static int
task_notify_func(struct notifier_block *self, unsigned long val, void *data)
{
struct task_struct *task = data;
- if (task == lowmem_deathpending) {
+
+ if (task == lowmem_deathpending)
lowmem_deathpending = NULL;
- task_handoff_unregister(&task_nb);
- }
+
return NOTIFY_OK;
}
@@ -174,14 +174,12 @@ static int lowmem_shrink(struct shrinker
selected->pid, selected->comm,
selected_oom_adj, selected_tasksize);
/*
- * If CONFIG_PROFILING is off, then task_handoff_register()
- * is a nop. In that case we don't want to stall the killer
- * by setting lowmem_deathpending.
+ * If CONFIG_PROFILING is off, then we don't want to stall
+ * the killer by setting lowmem_deathpending.
*/
#ifdef CONFIG_PROFILING
lowmem_deathpending = selected;
lowmem_deathpending_timeout = jiffies + HZ;
- task_handoff_register(&task_nb);
#endif
force_sig(SIGKILL, selected);
rem -= selected_tasksize;
@@ -199,6 +197,7 @@ static struct shrinker lowmem_shrinker =
static int __init lowmem_init(void)
{
+ task_handoff_register(&task_nb);
register_shrinker(&lowmem_shrinker);
return 0;
}
@@ -206,6 +205,7 @@ static int __init lowmem_init(void)
static void __exit lowmem_exit(void)
{
unregister_shrinker(&lowmem_shrinker);
+ task_handoff_unregister(&task_nb);
}
module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
Patches currently in stable-queue which might be from
[email protected] are
queue-3.3/staging-android-lowmemorykiller-don-t-unregister-notifier-from-atomic-context.patch
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